With recent prevalence of digital broadcasting, a digital video recording apparatus, a personal computer, etc. have been developed for recording digital videos comprising image and audio on a hard disk. The digital video recording apparatus, in which digital videos can possibly be compressed at a high rate, is capable of recording a number of image programs (TV programs). Further, with an appearance of a digital video disk-random access memory (DVD-RAM) changer and an increase in capacity of hard disk, it has been possible to record further more image programs as digitized.
To retrieve such the recorded image programs, there are such methods available for retrieving the recorded images by fast-forwarding or rewinding them as watching them actually or attaching indexes to image programs when recording them beforehand so that a viewer may retrieve his or her desired one of the image programs as watching the indexes listed on a screen.
Further, as more and more image broadcasts (TV broadcasts) have been digitized, program information on the image programs has been broadcast with it being superimposed on images. It is generally referred to as an electronic program guide (EPG). The EPG includes keywords of categories (genres), titles (program names) of image programs, and performers. In present-day digital satellite broadcasting, this EPG is displayed on a screen to enable retrieving a desired channel. Further, started has a broadcasting service with an EPG being embedded in a vertical blanking interval (VBI), which is a blank region in a surface wave.
With advancing of such the broadcasting service, a method has been proposed for using information in the EPG as a retrieval index. In this case, when an image program is recorded, an EPG of this image program is also saved on a hard disk etc. Then, when the recorded image programs (hereinafter referred to as “recorded programs” also) are viewed, tiles of the recorded programs are displayed as listed on a TV screen. Accordingly, a user retrieves his or her desired one of the programs on a list of their titles.
By this recorded program retrieval method, an EPG that indicates contents of programs such as their titles is displayed in a list on a TV screen, thus allowing the user to look for his or her desired recorded program with confirming the program titles etc., which is convenient.
Furthermore, utilizing the above-mentioned EPG allows program-recording functions to be also sophisticated. For example, it is also possible to instruct recording of an image program directly from its title or to specify a keyword of a category or a performer included in the EPG to record a program that matches this keyword automatically. Further, as disclosed in Japanese Patent Application Publication No. 2000-253325, a method is known for analyzing a user's viewing history to record apparent programs of his preference automatically and present a predetermined recommendation degree to the user.
Note here that by the conventional method for retrieving recorded programs, a user has looked for his or her desired program with him or her actually watching images of recorded programs by fast-forwarding or rewinding them. Therefore, the user needs to perform complicated and troublesome operations such as fast-forwarding or rewinding with him or her watching a TV screen and also specify his or her desired program based on his or her memory and so is burdened heavily, which is a problem.
Further, by the method for attaching indexes to programs when they are recorded so that a user may look for his or her desired one of the programs in a list of these indexes displayed on a screen, the user retrieves the image programs based on the indexes and so is less burdened somewhat than the one in the case where he or she is engaged in fast-forwarding or rewinding. However, information of the indexes comprises only recorded date and time, so that there still exists a problem that other information must depend on user's hunch and memory. In particular, in the case of automatic recording of image programs, it is extremely difficult for a user to recall contents of the recorded programs only from the recorded date and time, thus giving rise to a problem that the more saved image programs, the more burdens are inflicted on the user.
Further, according to the retrieval assisting method by use of the above-mentioned EPG, recorded programs as well as the EPG have been saved beforehand so that a user may watch a list of title of the recorded programs displayed on a screen when he or she views them.
Accordingly, if too many recorded programs are saved, their titles overflow from one screen when they are listed, thus giving rise to a problem that retrieval of indexes becomes troublesome. Further, in a case where programs are automatically recorded together with their titles, it may be difficult for the user to recall contents of the programs only from its program information.